Previously these tests required you to run them with the root of the
Zulip repository as the current working directory, just due to
sloppiness.
We clean this up, while also making the path handling more consistent
and involving less fragile code.
Fixes#4169.
This directory contains scripts that are used in building, managing,
testing, and other forms of work in a Zulip development environment.
Note that tools that are also useful in production belong in
scripts/ or should be Django management commands.